ABSTRACT ARCHIVE

Successes and failures of vertical HIV transmission prevention efforts in Canada: evidence from the Canadian Perinatal HIV Surveillance Program (CPHSP)

Background: The CPHSP collects data annually
on HIV infected mothers and their infants from 22 Canadian pediatric and HIV centres across the country. The
objective of this report was to describe factors associated with VT in Canada since
2004, post-implementation of routine prenatal HIV testing programs in all
provinces/territories.Methods: All children born in Canada to HIV-infected mothers from
2004-2013 in the CPHSP database were reviewed. VT rates are based on data of
MIP delivered in Canada
and identified within 3 months after birth; infants identified beyond 3 months
of birth are tracked separately.Results: Among 1996 MIPs, 1984 (99%) were identified
antenatally or within 3 months of the child''s birth. Of these, 93% were
prescribed antenatal combination antiretroviral therapy (acART), 85% >4
weeks before delivery, and 8.5% ≤4 weeks before delivery. Intrapartum intravenous
zidovudine was administered to 88% of mothers and ≥4 weeks of antiretroviral prophylaxis was
given to 96.4% of neonates. The VT rate for this cohort was 1.7% (33 infants);
the rate was 14.6% with no acART, 6.6% with ≤4 weeks of acART before delivery and 0.12%
with >4 weeks of acART before delivery. Of two VT cases that occurred
despite >4 weeks of acART, one was associated with poor maternal adherence,
the other with incomplete virologic suppression despite good adherence. An
additional 12 infected infants were identified after 3 months of age. Eight of
these 12 mothers were Canadian born (4 white, 4 Aboriginal) and 11/12 delivered
in provinces with opt-out antenatal screening programs. On multivariate
analysis of all 1996 MIP, receipt of no/≤4 weeks versus >4 weeks of acART was
significantly associated with earlier year of birth, province/territory of
birth and maternal risk acquisition category (28.4% IDU; 11.6% sex; 12.3% other)
(all p< 0.01).Conclusions: VT continues to occur in Canada despite a free universal access healthcare
system. The observations that 12/45 infected infants were identified after 3
months of age and that 11/12 of those were in provinces with opt-out prenatal
screening programs suggest that lack of access to routine prenatal care is a
major issue contributing to ongoing VT in Canada.